A POSCO employee works at the steelmaker's plant in Pohang, North Gyeongsang Province, June 24. Courtesy of POSCO

POSCO's unionized workers voted on Monday to take collective action, putting the steelmaker at risk of facing the first strike in its 56-year history.

According to the steelmaker's leading union affiliated with the Federation of Korean Trade Unions, 72.25 percent of its 7,934 members voted for job actions, allowing the workers to secure the lawful right to strike or take other actions reducing productivity in their workplace.

The vote took place on the day when POSCO apologized to residents of Pohang, North Gyeongsang Province, for a fire that day at its main steel mill in the city, which broke out just two weeks after the previous fire at the same facility.

Amid the worsening profitability of the steelmaking industry, POSCO's labor and management have locked horns over wage negotiations, as the company has refused to accept the union's request for an 8.3 percent hike in the base wage and provision of bonuses equivalent to 300 percent of each employee's monthly base wage.

Last Thursday, the National Labor Relations Commission decided to end its arbitration on the collective bargaining negotiations between the steelmaker's labor and management, as the two sides failed to narrow their differences.

If POSCO's union decides to walk out, it will be the first such action since the company's founding in 1968.

However, the union is said to remain cautious about staging a strike, as the management intends to continue wage negotiations. Last year, POSCO and its labor union experienced a similar standoff, but reached a last-minute agreement.